The MLLA Megger low level adaptor has been designed to filter the low-level outputs from the latest version of voltage/current generators in the Megger SMRT series and FREJA 500 series test sets. In Rogowski mode, the current channels will convert from a current source to a millivolt source. This will allow the current channel to simulate a low-level voltage source from a Rogowski coil and the MLLA can filter these low-level outputs.
There are three ranges for the Rogowski outputs: 2, 10, and 40 V. When in the low voltage mode, the voltage channel provides 0 to 2 V with high resolution and accuracy. Use the low-level outputs available on the latest versions of SMRT and FREJA relay test sets for testing relays, which use low voltage signals from non-conventional current transformers (CTs) and voltage transformers (VTs) such as Rogowski coils and CVTs.
The current and voltage channels can be configured to simulate low-level outputs using relay testing management software (RTMS) on an SMRT or FREJA 500 series unit. Low-level outputs are available from the voltage and current channel output terminals through the individual MLLA low-level filters. For testing relays like the ABB REF615 and Siemens 7SJ81, the low-level filters provide the interface between the SMRT/FREJA relay test set’s converted low-level output terminals and the low-level signal interface cables to the relay under test.
